Pilgering mill



Jan. 28,' 1930. BAMBERGER 1,744,731

PILGERING MILL Filed March 25, 1926 Fig.2.

V by

L s. W Attorney.

Patented Jan. 28, 1930 UNITED STATES PATENT OFFICE OTTO BAMBERGER, 0FDUISB'URG, GERMANY, ASSIGNOR TO IlJEUTSCHE MASOHINEN- FABRIKAKTIENGESELLSCHAFT, 0F DUISBURG, GERMANY PILGERING MILL Applicationfiled March 25, 1926, Serial No. 97,329, and in Germany February 6,1926.

The present invention relates to driving gear for the feeding mechanismof pilgering mills.

Hitherto the various movements of the feeding mechanism were effected byhydraulic means.

The method of operating thefeeding mechanism renders necessary varyingpowers and speeds; On the oneehand the blank, which is placed upon themandrel, is very quickly rolled, while on the other hand the actualpilgering proceeds slowly in exactly uniform finely graduated forwardmovements of the blank. After the tube has been rolled, the feedingmechanism is used for withdrawing the mandrel from the completed tube,for which operation very considerable power must be employed. Thefeeding mechanism must then be rapidly retracted whereby the consequentplacing of a new hollow block upon the mandrel requires the expenditureof considerable power.

Provision for the changing requirements in connection with the hydraulicfeeding mechanism hitherto employed could be niade only by employingcomplicated controlling devices, and attention to them was troublesome,with the consequence that the apparatus was frequentlyput out of order.Furthermore, the solution of the problems involved in working byhydraulic m'eans necessitates apparatus that is expensive, indeed it wasusually necessary to install a special source of power for the feedingmechanism. The present invention solves the practical difficulties in asimple and effective way.

According to the invention the carriage for the blank isdriven by one ormore electric motors in the use of gearing, in such manner that bygraduating or dividing the drive the appropriate power and speed areexerted on the carriage.

It is particularly advantageous to use two electric motors for thedrive, one of which runs at a high speed and does considerable work byadvancing the blank to and withdrawing it from the mill, and alsoremoving the blank from and replacing it on the mandrel, while the othermotor, working at a considerably lower speed and doing far less work,advances the blank during the rolling operation.

It is furthermore advantageous to arrange the motors in such manner thatthey can be put into and out of operation by an electrical switch or bycoupling or uncoupling as desimplicity of the whole arrangement thepossible sources of error are reduced to a minimum.

The invention is illustrated diagrammatically in the accompanyingdrawings by way of example:

Figure 1 is a plan of the mechanism,

Figure 2 is an elevation,

Figure 3 is a partial side elevation, and

Figure 4 is a longitudinal sectional elevation, to an enlarged scale,showing the rear portion of the mechanism to which the inventionrelates.

The pilgering rolls are indicated by a. The blank or hollow block b ismounted upon a mandrel b, which is loosely mbunted on the carriage dwith an automatic retracting device interposed. The carriaged comprisesa cylinder having a piston the rod of which forms or is connected to therifled spindle to which the mandrel b is secured. The iston is subjectedto air pressure by means 0 compressed air supplied from a suitablereservoir or container. Thus when the blank is worked by the rolls a, itis forced backwards against the air pressure and when released by therolls is thrown forward by the air pressure acting upon the piston. Thecarriage d is moved upon guide rails by the means of spindles 0.

- power is applie The spindles c are moved by toothed wheels e-mounte-dupon them, with which toothed wheels engage a pinion mounted upon theshaft of the motor f. h is the second driving motor connected throughthe clutch g to the motor f by means of a worm wheel drive is, the shaftof the motor f carrying the worm is, while the worm wheel 7.: is, forexample, mounted on a short shaft in alignment with the shaft of themotor f and adapted to be coupled thereto by the clutch g, or upon asleeve carried by an extension of the shaft of the motor 7, the sleevebeing engaged therewith by the clutch g.

The mechanism is operated as follows:

The hollow block is first placed upon the mandrel. As for this purpose agreat consumption of power is necessary, the operator switches in themore powerful motor 7, and throws out the clutch g. After the hollowblock has been placed in position, the same source of power feeds theblank at a considerable speed 11 to a position in front of the pilgeringrol s. Here the current is passed through the motor I) and the clutch gis engaged. Thereupon the the motor 71-, which is now energized, drivesthe worm gearing k, k and, through the clutch g, the shaft of the motorf with the armature and thus, through the toothed wheels 6 of thespindle 0, moves the blank slowly forward through the pilgering rolls.If there are any interruptions during pilgering, that is to say, if theblock should am by reason of flaws in the metal, the blank may at alltimes be assisted over the diflicult part by the motor f, or the blankmay be quickl drawn back.

When the pi gering operation is completed the motor his cut out and themore owerful motor f comes into operation and withdraws the mandrel bfrom the finished tube, retracts the feeding mechanism at a high speedand places a new hollow block upon the mandrel.

I claim:

1. Feeding mechanism for pilgerin mills consisting in combination, amandre upon which the blank is applied, means com ri 'n an electricmotor ada ted to cause 51c ed vancement of the sai mandrel and itsretraction from the pilgering rolls, a separate smaller electric motoradapted to advance the blank durin the pilgermgoperation, and meanswhere y either motor may be set into blank from and applying a new blankon the said mandrel, a second smaller electric motor adapted to advancethe blank during the pilgering operation, and means whereby either motormay be set into operation to move the blank and the mandrel,substantially as hereinbefore described.

3. Feeding mechanism for pilgerin mills consisting in combination of amandre upon which the blank is applied, a carriage upon which themandrel is supported and by which the mandrel is advanced to andretracted from the pilgering rolls, gear through which power is appliedto the said carria e, an electric motor adapted for the operation of thesaid gear in advancing the mandrel and retracting it and in removing thefinished blank from and replacing a new blank on the said mandrel, asecond smaller electric motor adapted to advance the blank during thepilgermg operation, and means comprising a clutch'through which thedrive may be 1mparted to the said gear from the second smaller electricmotor, substantially as hereinbefore described.

' OTTO BAMBERGER.

operation to move the blank and themhndrel" substantially ashereinbefore described.

2. Feeding mechanism for pilgerin mills consisting in combination amandre upon which the blank is applied, a carriage upon which themandrel is supported and by which the mandrel is advanced to andretracted from the pilgerin rolls, gear through which to the said carriaan electric motor ada ted for the operation of the said gear in a.vaneing the mandrel and retracting'it and in removing the finished

